A latch assembly for keeping doors, windows, shutters and the like in a closed position is disclosed in U.S. Pat. No. 4,548,432. The known assembly comprises a lock casing attached for example via rivets to an espagnolette edge bar. The bar and the lock casing are arranged to be accommodated in a recess in a door. The lock casing houses operating elements responsive to movement of a handle on the lock casing for manoeuvring at least one bolt from a retracted position to an extended position and back. The operating elements include an espagnolette rod emerging from the lock casing and running parallel to the edge bar from the lock casing to the bolt or bolts. Operation of the handle on the lock casing causes displacement of the espagnolette rod which, in turn, effects displacement of the bolt or bolts.
Depending on the chosen application, different demands are placed on latch assemblies. For example, for a window application, it is not always necessary that the latch assembly be lockable with a key-actuated lock. In other applications, for example on some doors in business premises, it is necessary that the door be openable from one side without the use of a key, though openable from the other side solely with the use of a key. Thus, different operating modes are required of latch assemblies depending on the circumstances of the chosen application.
Since the espagnolette rod of the above-described known latch assembly is an integral part of the operating elements of the lock housing, a unique latch assembly comprising lock housing, espagnolette edge bar and bolt, together with associated operating elements, must be produced for each different chosen application.